Magnetoelastic properties of polymer-bonded Sm 0.88Dy 0.12Fe 1.93 pseudo-1–3 composites

Abstract

Pseudo-1–3 magnetostrictive composites of approximately 0.6 volume-fraction Sm 0.88Dy 0.12Fe 1.93 particles and epoxy were fabricated, and their quasi-static and dynamic magnetoelastic properties were investigated. The dynamic relative permeability ( μ r 33 ) exhibited a flat response with frequency, except for the variation associated with the fundamental shape resonance of the samples at about 46 kHz. Both μ r 33 T (at constant stress) and μ r 33 S (at constant strain) reached their maximum values at a magnetic bias field ( H Bias ) of about 20 kA/m due to the relatively easy 180° domain-wall motion. The two elastic moduli, E 3 H (at constant magnetic field strength) and E 3 B (at constant magnetic flux density), showed a small decrease with increasing H Bias with no trace of negative - Δ E effect in the H Bias range of 5–240 kA/m. The saturation magnetostriction ( λ S ) was not attained at the highest available field level, reflecting the existence of relatively high magnetocrystalline anisotropy in the material. The dynamic strain coefficient ( d 33 ) displayed a broad negative maximum around H Bias = 180 kA / m as a result of the maximum motion of non-180° domain walls.